Because of the repetitive trauma to the upper extremities that results from wheelchair propulsion, the prevalence of pain and injury in manual wheelchair users is alarmingly high. By understanding the mechanisms in the development of arm pain, we can begin to prevent the pain. The SMART(Wheel) is a tool that enables direct measurement of the forces and torques applied by wheelchair users to the pushrim. This capability allows for investigations into the cause of injuries, and can lead to specific recommendations to improve efficiency and reduce the risk of injury. The specific aims in Phase II of this research are to: 1) Identify additional characteristics in a force/moment measure system (e.g., display content and layout) that are desired by clinicians; 2) Further refine the design of the Clinical SMART(Wheel) (both hardware and software components) to maximize its functionality for commercial use; 3) Conduct clinical testing to verify that the performance of the newly designed "Clinical SMART(Wheel)" is useful clinically; 4) Conduct off-site trials with manual wheelchair users to demonstrate the usability and effectiveness of the Clinical SMART(Wheel) in clinical or other environments. The culmination of this research will be a commercially viable product available to research laboratories, seating/wheelchair clinics, wheelchair and accessory manufacturers, ADA consultants, and manufacturers of accessible surfaces (e.g. playgrounds, parks, etc.). PROPOSED COMMERCIAL APPLICATION: The SMART(Wheel) will be a valuable tool for rehabilitation research labs, seating/wheelchair clinics, and wheelchair manufacturers. Many have already purchased SMART(Wheel)s, even when earlier versions of the SMART(Wheel) were less user-friendly. Because the SMART(Wheel) also facilitates the evaluation of the accessibility of surfaces, it will also be an important tool for ADA consultants, architects, regional planners, and manufacturers of accessible surfaces (e.g. playgrounds, parks, etc.).